English

Generically log smooth families via generators and relations

Algebraic Geometry 2026-02-20 v1

Abstract

Let f ⁣:XAt1f\colon X \to \mathbb{A}^1_t be an affine flat morphism of finite type, and let V=f1(0)V = f^{-1}(0). Then, we obtain a morphism of log schemes f ⁣:(XV)(At10)f\colon (X|V) \to (\mathbb{A}^1_t|0). In this article, we develop algorithmic tools to study the log-geometric properties of ff by means of a presentation Γ(X,OX)=k[t,x1,,xn]/(f1,,fr).\Gamma(X,\mathcal{O}_X) = \Bbbk[t,x_1,\ldots,x_n]/(f_1,\ldots,f_r). We obtain similar tools for projective flat morphisms when the homogeneous coordinate ring is given by generators and relations. We provide an implementation of our algorithms in Macaulay2. In a slightly different direction, we give some results on the sheaf LSV\mathcal{LS}_V of log smooth structures on a toroidal crossing scheme (V,P,ρˉ)(V,\mathcal{P},\bar\rho).

Keywords

Cite

@article{arxiv.2602.17617,
  title  = {Generically log smooth families via generators and relations},
  author = {Simon Felten},
  journal= {arXiv preprint arXiv:2602.17617},
  year   = {2026}
}

Comments

57 pages, 2 figures

R2 v1 2026-07-01T10:43:18.795Z